* Expects to add HK primary listing by end-2022, keep NYSE listing

* HK shares jump nearly 6%; move will diversify investor base -CEO

* Seen boosting mainland China investor access to Alibaba shares

* In line with move Ant Group execs step down from Alibaba partnership (Adds context on secondary listings in Hong Kong and closing share price in paragraphs 4 and 5)

By Josh Horwitz and Scott Murdoch

SHANGHAI/HONG KONG, July 26 (Reuters) - Alibaba plans to add a primary listing in Hong Kong to its New York presence, targeting investors in mainland China as it becomes the first big company to take advantage of a rule change in the financial hub to attract high-tech Chinese firms.

The e-commerce giant's move, announced on Tuesday, comes as both Washington and Beijing sharpen scrutiny over Chinese companies' listings, and after a devastating regulatory crackdown in China left Alibaba with a $2.8 billion fine and scuppered an initial public offering (IPO) of its affiliate Ant Group.

It also comes against the backdrop of an audit dispute between China and the United States, which is threatening to kick out hundreds of Chinese companies listed in New York.

Analysts said the change should give mainland China investors easier access to the shares via a link to the Hong Kong bourse known as the Stock Connect. Secondary listings in Hong Kong, like Alibaba's current listing, are not allowed in the Stock Connect trade.

The shares climbed 4.8% by the close of trading, while the Hong Kong benchmark gained 1.7%.

"Being in Stock Connect means it will be more convenient for mainland Chinese investors to eventually buy the stock, so investors are happy to step in today and buy the stock in Hong Kong," says Louis Tse, managing director of Wealthy Securities.

Already present on the Hong Kong bourse with a secondary listing since 2019, Alibaba said it expects the primary listing to be completed by the end of 2022. Chief Executive Daniel Zhang said the dual listing would foster a "wider and more diversified investor base".

The move comes after the Hong Kong Stock Exchange (HKEX) in January changed its rules to allow "innovative" Chinese companies - operating an internet or other high-tech business - with weighted voting rights or variable interest entities (VIE) to carry out dual primary listings in the city.

Under a VIE structure, a Chinese company sets up an offshore entity for overseas listing purposes that allows foreign investors to buy into the stock.

"Hong Kong is also the launch pad for Alibaba's globalisation strategy, and we are fully confident in China's economy and future," Alibaba's CEO Zhang said in a statement.